<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>045-盒模型分类.html</title>
	<style>
		*{
			margin: 0;
			padding: 0;
		}
		div{
			width: 100px;
			height: 100px;
			padding: 20px;
			border: 10px solid #000;
			margin: 10px;
			background-color: #800;
		}
		.box{
			box-sizing: content-box;
		}
		.box1{
			box-sizing: border-box;
		}
	</style>
</head>
<body>
	<div class="box"></div>
	<div class="box1"></div>
</body>
</html>